Smashed Chickpea Salad Sandwich

Ingredients

• One 15-ounce can chickpeas, rinsed and drained
• 1 celery stalk, diced
• 2 or 3 tablespoons mayonnaise or Greek yogurt
• 1 or 2 teaspoons spicy brown mustard (or any mustard)
• Freshly squeezed lemon juice, as needed
• Kosher salt
• freshly ground black pepper
• 1 teaspoon crushed red pepper flakes, plus more as needed
• Pickled pepperoncini or pickled jalapeños, sliced, as needed
• Toasted sliced bread, for serving
• 1 or 2 scallions, thinly sliced (or a few chives, chopped)
• Flaky salt, as needed